A biology teacher was asking his class;"what part of the human body grows bigger when they are excited?" The teacher points towards a girl sitting in front of the class and asked this question. Suddenly the girl's face turned red then looked away and answered:"That...that....sorry teacher, I can't answer that." The girl's face just turned redder and she looked down due to embarassment. So the teacher proceded with the question by asking a guy next to her, and the guy replied;"the pupil."